diff --git a/src/network/bmobject.py b/src/network/bmobject.py
index 249ec2ab..267cac58 100644
--- a/src/network/bmobject.py
+++ b/src/network/bmobject.py
@@ -8,23 +8,28 @@ from network.dandelion import Dandelion
 import protocol
 import state
 
-class BMObjectInsufficientPOWError(Exception): pass
+class BMObjectInsufficientPOWError(Exception):
+    errorCodes = ("Insufficient proof of work")
 
 
-class BMObjectInvalidDataError(Exception): pass
+class BMObjectInvalidDataError(Exception):
+    errorCodes = ("Data invalid")
 
 
-class BMObjectExpiredError(Exception): pass
+class BMObjectExpiredError(Exception):
+    errorCodes = ("Object expired")
 
 
-class BMObjectUnwantedStreamError(Exception): pass
+class BMObjectUnwantedStreamError(Exception):
+    errorCodes = ("Object in unwanted stream")
 
 
-class BMObjectInvalidError(Exception): pass
+class BMObjectInvalidError(Exception):
+    errorCodes = ("Invalid object")
 
 
 class BMObjectAlreadyHaveError(Exception):
-    pass
+    errorCodes = ("Already have this object")
 
 
 class BMObject(object):
diff --git a/src/network/bmproto.py b/src/network/bmproto.py
index 17b2c761..47c6c858 100644
--- a/src/network/bmproto.py
+++ b/src/network/bmproto.py
@@ -24,13 +24,16 @@ import shared
 import state
 import protocol
 
-class BMProtoError(ProxyError): pass
+class BMProtoError(ProxyError):
+    errorCodes = ("Protocol error")
 
 
-class BMProtoInsufficientDataError(BMProtoError): pass
+class BMProtoInsufficientDataError(BMProtoError):
+    errorCodes = ("Insufficient data")
 
 
-class BMProtoExcessiveDataError(BMProtoError): pass
+class BMProtoExcessiveDataError(BMProtoError):
+    errorCodes = ("Too much data")
 
 
 class BMProto(AdvancedDispatcher, ObjectTracker):
diff --git a/src/network/proxy.py b/src/network/proxy.py
index 7d46cd86..96930c18 100644
--- a/src/network/proxy.py
+++ b/src/network/proxy.py
@@ -10,7 +10,7 @@ import state
 class ProxyError(Exception):
     errorCodes = ("UnknownError")
 
-    def __init__(self, code):
+    def __init__(self, code=-1):
         self.code = code
         try:
             self.message = self.__class__.errorCodes[self.code]